Free · Health · Pregnancy & Cycle
Conception Calculator
Estimate likely conception and fertile-window dates from a period date, due date, or known birth date.
- Checked formula
- Private in your browser
- No signup
Result
Your calculation
- Estimated conception
- Sunday, February 15, 2026
- Likely fertile window
- Tuesday, February 10, 2026 to Monday, February 16, 2026
- Estimated last period
- Sunday, February 1, 2026
- Estimated due date
- Sunday, November 8, 2026
This is a calendar estimate. Conception cannot usually be identified to a single date without assisted-reproduction records.
How to use this calculator
- Enter current measurements as accurately as practical.
- Calculate to see the estimate, range, and method details.
- Use the result as context, and discuss health decisions with a qualified clinician.
Use the result with context
Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.